High-performance large-area quasi-2D perovskite light-emitting diodes

Abstract

Serious performance decline arose for perovskite light-emitting diodes (PeLEDs) once the active area was enlarged. Here we investigate the failure mechanism of the widespread active film fabrication method; and ascribe severe phase-segregation to be the reason. We thereby introduce L-Norvaline to construct a COO−-coordinated intermediate phase with low formation enthalpy. The new intermediate phase changes the crystallization pathway, thereby suppressing the phase-segregation. Accordingly, high-quality large-area quasi-2D films with desirable properties are obtained. Based on this, we further rationally adjusted films’ recombination kinetics. We reported a series of highly-efficient green quasi-2D PeLEDs with active areas of 9.0 cm2. The peak EQE of 16.4% is achieved in <n > = 3, represent the most efficient large-area PeLEDs yet. Meanwhile, high brightness device with luminance up to 9.1 × 104 cd m−2 has achieved in <n> = 10 film.

Phosphonate/Phosphine Oxide Dyad Additive for Efficient Perovskite Light‐Emitting Diodes

“…Figure 4d shows the normalized EL spectra at a voltage of 5 V. All the PeLEDs demonstrate similar green emission with a FWHM of 22 nm. Differing from other strategies to improve radiative recombination with a large spectra shift of > 10 nm, [11,26] the maximum EL peak shift is only 2 nm on introducing these additives.…”

“…Notably, the EL efficiency of PE-TPPO-modified PeLEDs is much higher and the current density to achieve the highest EQE is largely reduced, suggesting the enhanced carrier radiative recombination under low injected carrier concentration, which is generally reported due to the formation of perovskite domains with increased quantum confinement and/or reduced crystal size. [25,26] Here, we exclude the former by considering the unchanged absorption edges (Figure 3a) and normalized PL spectra excited from both glass and film sides (Figure S6). The latter is investigated by X-ray diffraction (XRD) measurement (Figure S7).…”

Phosphonate/Phosphine Oxide Dyad Additive for Efficient Perovskite Light‐Emitting Diodes

“…Figure 4d shows the normalized EL spectra at a voltage of 5 V. All the PeLEDs demonstrate similar green emission with a FWHM of 22 nm. Differing from other strategies to improve radiative recombination with a large spectra shift of >10 nm, [11, 26] the maximum EL peak shift is only 2 nm on introducing these additives.…”

“…Thus, passivating defects to increase the device efficiency is confirmed for PE‐TPPO. Notably, the EL efficiency of PE‐TPPO‐modified PeLEDs is much higher and the current density to achieve the highest EQE is largely reduced, suggesting the enhanced carrier radiative recombination under low injected carrier concentration, which is generally reported due to the formation of perovskite domains with increased quantum confinement and/or reduced crystal size [25, 26] . Here, we exclude the former by considering the unchanged absorption edges (Figure 3a) and normalized PL spectra excited from both glass and film sides (Figure S6).…”

Advances and Challenges in Two-Dimensional Organic–Inorganic Hybrid Perovskites Toward High-Performance Light-Emitting Diodes

“…After that, materials with similar structure to CaTiO 3 are called perovskite. The formula of three-dimensional (3D) halide perovskite is ABX 3 (A = MA + , FA + , Cs + , Rb + , K + ; B = Pb 2+ , Cu 2+ , Sn 2+ ; X = Cl − , Br − , I − ) [11][12][13][14][15][16][17][18][19][20][21].…”